If I try wget
it downloads the resolved page. But I want to download the original script. Is this possible?
"Officially" - no.
Through "hacking" - yes. If a website allows to download some content via "/download.php?src=path_to_file" script, AND it was unproperly coded, then you could request to download, say, index.php file.
Check this out: https://www.owasp.org/index.php/Path_Traversal
This is not possible, the webserver doesn't output the PHP script. The webserver parses it serverside and writes the response of that to the client.
No, and thank goodness for that. The server is completely in control of how it responds to your HTTP requests.
Strictly speaking, you can't tell whether it's PHP on the other end of the wire in the first place.
No this is not possible, and would be a huge security issue if it was.
The only way this would be possible is if the web server (Apache) was not configured correctly